without sudo, i got this

[    0.170000]  ubda: unknown partition table
[    0.170000] Warning: Assigning a globally valid ethernet address to a device
[    0.170000] You should set the 2nd rightmost bit in the first byte of the MAC,
[    0.170000] i.e. 02:50:f9:00:00:66
[    0.170000] Netdevice 0 (00:50:f9:00:00:66) :
[    0.170000] TUN/TAP backend - IP = 10.50.181.51
[    0.200000] EXT3-fs (ubda): error: couldn't mount because of unsupported optional features (240)
[    0.210000] EXT2-fs (ubda): error: couldn't mount because of unsupported optional features (244)
[    0.220000] EXT4-fs (ubda): INFO: recovery required on readonly filesystem
[    0.220000] EXT4-fs (ubda): write access unavailable, cannot proceed
[    0.300000] UDF-fs: No partition found (1)
[    0.330000] NILFS: Can't find nilfs on dev ubda.
[    0.360000] GFS2: gfs2 mount does not exist
[    0.360000] List of all partitions:
[    0.360000] 6200          100000 ubda  driver: uml-blkdev
[    0.360000] No filesystem could mount root, tried:  reiserfs ext3 ext2 ext4 squashfs vfat msdos iso9660 ntfs fuseblk udf nilfs2 btrfs gfs2 gfs2meta
[    0.360000] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(98,0)
[    0.360000] 0fc6bedc:  [<084d18bc>] dump_stack+0x1c/0x20
[    0.360000] 0fc6bef4:  [<084d190d>] panic+0x4d/0x13f
[    0.360000] 0fc6bf28:  [<08048ca5>] mount_block_root+0x20d/0x21c
[    0.360000] 0fc6bf78:  [<08048d00>] mount_root+0x4c/0x54
[    0.360000] 0fc6bf9c:  [<08048e54>] prepare_namespace


> From: rob0@gmx.co.uk
> To: user-mode-linux-user@lists.sourceforge.net
> Date: Fri, 2 Dec 2011 15:50:50 -0600
> Subject: Re: [uml-user] Can i run uml in the background ?
>
> On Friday 02 December 2011 15:10:35 ning ji wrote:
> > Guess the answer is yes,but when i run
> > #sudo ./umlinux ubda=./fs6 mem=128M
> > eth0=tuntap,,00:50:F9:00:00:65,10.50.181.51 & i got this
> > [1]+ Stopped sudo ./umlinux ubda=./fs6 mem=128M
> > eth0=tuntap,,00:50:F9:00:00:65,10.50.181.51
> >
> > Any hints pls ?Thanks !
>
> Why are you running this as root? There are safe ways to set up
> networking while maintaining reduced privilege in the UML instance
> itself.
>
> Can you background it as non-root?
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